ATLANTA (AP) _ Donald Sonner is in the junk business. The 64-year-old head of Southern Bloomer Manufacturing in Bristol, Tenn., takes scrap cloth and makes underwear for prisons and strips for cleaning guns.

He doesn't have a master's degree in business. In fact, he went to high school for only a year. But by working hard and capitalizing on an idea no one else had, Sonner was a millionaire by the time he was 24.

His story is not unique, says Thomas J. Stanley, who surveyed 1,300 millionaires for his new book, ``The Millionaire Mind,'' which comes out today.

The average millionaire made B's and C's in college, Stanley says. Their average SAT score was 1190 _ not good enough to get into many top-notch schools. In fact, most millionaires were told they were not smart enough to succeed.

``I find no correlation between SAT scores, grade point averages and economic achievement. None,'' said Stanley. ``Admittedly, there are some very bright people in the data, but not many.''

Instead of relying on natural genius, millionaires choose careers that match their abilities, Stanley said. They may not have great analytic intelligence, but they are creative and practical. They focus on a goal, take calculated risks and then work harder than most people.

It's a lesson Stanley has taken to heart. The author, who lives in Atlanta, has gotten rich himself by writing about the rich.

For years he was a marketing professor at Georgia State University. He wrote three textbooks about marketing to wealthy people and gave seminars around the country. But he felt like he was on a treadmill going nowhere.

So he took time off to write ``The Millionaire Next Door,'' which was penned with researcher William D. Danko of Albany, N.Y. Published in 1996, it has been on The New York Times Best Sellers list for more than 150 weeks.

``The book went No. 1 _ not bad for somebody who got all C's in English,'' Stanley said. ``The reason the book succeeded is not because I'm a great writer. It's not Shakespeare. The fact is I picked the right target.''

Stanley found the key to being rich is being frugal. He says most millionaires live beneath their means, driving domestic cars and living in upper-middle class neighborhoods.

In ``The Millionaire Mind,'' Stanley studied even richer millionaires _ the top 1 percent of households. These people had an average net worth of $9.2 million and earned $749,000 a year.

The average multimillionaire in Stanley's study is a 54-year-old man, married to the same woman for 28 years, with three children. Nearly half are business owners or senior corporate executives.

And almost none of them credit their success to being smart. They say the keys to success are being honest and disciplined, getting along with people, having a supportive spouse and working hard.

``Somehow they figured out what they were good at,'' Stanley said. ``They all said, 'I'll be the best at this. This is what I really, really love to do.'''

``The Millionaire Mind'' is a hybrid _ part science and part inspirational self-help book. Stanley crunched numbers using the help of his friend and associate Jon Robbin, a Harvard-trained mathematician. But its message is instructive: Anybody can be a millionaire.

``Nobody should tell kids they can't succeed based on test scores,'' Stanley said.